1. Field of the Invention
The present invention relates to a method and device for detaching an electrolytically precipitated metal sheet, especially a copper, nickel or zinc sheet, from a base plate which works as a cathode and which is kept in an essentially vertical position.
2. Description of the Prior Art
The detachment of cathodally precipitated metal sheets (especially a copper, nickel, or zinc sheet) in an electrolytic system is usually achieved manually. Various tools are used for the detachment, such as a chisel or scrapers, which damage the base plate working as a cathode in long-term use and make the detachment from the scratched plate difficult. Various mechanized methods have been suggested to facilitate this working stage, which is of considerable technological and economic importance in the electrolytic production of metal. Some of these methods are detaching of the metal sheet with a suction cup device (Finnish patent application No. 1879/71), with a pneumatic or hydraulic spray device (U.S. Pat. No. 3,501,385 and Finnish patent application No. 2856/70), with a vibrator (Finnish patent application No. 3254/72), with vertically moving blades or a guillotine (Belgian Pat. No. 758,783), or by a rolling-mangling treatment. For example, German patent application No. 1,904,104 introduces a device provided with a detachment blade which moves up and down on both sides of the base plate over the entire height of the plate and which is guided by guide members so that during the detaching movement it is in contact with the plate and during the return movement it is clear from the plate. Furthermore, the device contains members for holding on to the base plate during the detachment operation and slanted side plates for receiving the detached copper sheets. Besides being mechanically complicated and expensive these known methods and devices either damage the base plate or are slow and poorly applicable to mass production. The yield of faultlessly detached sheets in proportion to the amount fed into the process also remains too low.